Communications by optical connection, in particular by infrared connection, take place between a transmitter that transmits the optical signal and a receiver that receives it. Because of losses, the energy of the optical signal transmitted by the transmitter is not entirely received by the receiver and the energy of the signal received may be low. In order to compensate for these losses and increase the energy of the received signal, a concentrator is placed in front of the receiver. This concentrator captures the beams that pass in the vicinity of the receiver and redirects them to the latter whilst focusing them, thus affording an increase in the energy of the received signal by concentration on the receiver.
Such an optical electromagnetic wave concentrator is described by Xin Yang in an article published by “SPIE Proceedings” of December 2002 (Proceedings of SPIE—Volume 4873—Optical Wireless Communications V, Eric J. Korevaar, Editor, December 2002, pp 71-78) under the title “Simulation of impulse response on IR wireless indoor channel with concentrator”.
The concentrator has the shape of a truncated sphere placed in front of a detector, the radius of which is greater than the radius of the detector, thus making it possible to redirect the incident beams that are outside the field of the detector towards the detector. This type of concentrator gives satisfaction if the energies of the various optical beams received by the concentrator are not too low and if the concentration of the beams makes it possible to achieve a certain energy level affording good detection of the signal; in particular the total energy must make it possible to have an advantageous signal to noise ratio.
One object of the present invention is to propose an amplifying optical electromagnetic wave concentrator that does not have the drawbacks of the prior art.